Hepatitis C virus core protein interacts with cellular putative RNA helicase

Area of Science:

• Virology
• Molecular Biology
• Gene Regulation

Background:

• Hepatitis C virus (HCV) nucleocapsid core protein exhibits trans-acting functions on viral and cellular promoters.
• Understanding the mechanism of HCV core protein's trans-activation is crucial for elucidating viral pathogenesis.

Purpose of the Study:

• To identify cellular proteins interacting with the HCV core protein.
• To investigate the functional consequences of the interaction between HCV core protein and its binding partners.

Main Methods:

• Yeast two-hybrid cloning system for protein-protein interaction screening.
• In vitro binding assays and in vivo co-immunoprecipitation to confirm interactions.
• Immunoblotting and indirect immunofluorescence for protein localization.
• Luciferase reporter assays to assess trans-activation activity.

Main Results:

• A DEAD box RNA helicase, designated CAP-Rf, was identified as an HCV core protein interactor.
• Direct interaction was confirmed between HCV core protein and CAP-Rf, with specific interaction domains identified.
• HCV core protein enhanced CAP-Rf's ATPase activity and potentiated its trans-activation of gene expression.
• CAP-Rf and HCV core protein colocalized in both the cytoplasm and nucleus.

Conclusions:

• CAP-Rf is a cellular RNA helicase involved in gene expression regulation.
• HCV core protein interacts with CAP-Rf, enhancing its trans-activation ability and modulating its ATPase activity.
• This interaction represents a potential mechanism by which HCV alters host gene expression, contributing to pathogenesis.